Rock-drill.



UNITED STATES PATENT OFFICE.

RALPH F. YOURTEE AND WILLIAM E. MAULL, OF ST. LOUIS, MISSOURI.

ROCK-DRILL.

To all 207mm it may concern:

Be it known that we, RALPH F. Youn'rnr. and lVILLIAir E. MAULL, citizensof the llnited States of America, residing at the city of St. Louis, inthe State of h/Iissouri, have invented new and useful Improvements inRock-Drills, of which the following is a specification.

This invention relates to rock drills, and one of the principal objectsof the same is to provide a drill of comparatively light weight so thatit may be carried from place to place without expensive moving machincryand which will operate rapidly and efliciently for its purpose.

Another object of the invention is to provide a rock drill designed tobe operated by a small gasolene motor.

Still another object of the invention is to provide friction gearing foractuating the cams for retracting the drill against the spring.

These and other objects may be attained by means of the constructionillustrated in the accompanyin drawings, in which Figure 1 is a sideelevation of a drill made in accordance with our invention. Fig. 2 is alongitudinal section part in elevation of the same on an enlarged scale.Fig. 3 is an enlarged end view of the same. Fig. 4 is an enlargedlongitudinal section of the drill shaft. Fig. 5 is an enlarged view ofone of the cams for operating upon. the trunnions of the drill shaft,said cam being in one of its positions. Fig. 6 is a similar enlargedview showing the cam in another of its positions. Fig. 7 is a transversesectional view of the drill shaft and its tubular bearing.

Referring to the drawings for a more specific description of ourinvention, the numeral 1 designates a suitable base having alongitudinal tubular guideway 2- mounted thereon, a feed screw 3 beingdisposed in the guideway and provided with a handle at for turning thesame, these parts being of the usual or any suitable construction.

A suitable motor 5 provided with a piston 6 is utilized for actuatingthe drill. The motor 5 is mounted upon a standard 5*, and the standard 5is supported in a guideway 6 at its base to permit the motor to slide inand out of the frame 11. The piston 6 has connected to it a piston rod 7connected to a crank shaft 8 extending across between two friction gearwheels 9 mounted upon a shaft 10 journaled in a frame 11. A similar pairSpecification of Letters Patent.

Application filed October 15, 1907.

Patented Jan. 11, 1910.

Serial No. 397,514.

of friction wheels 11 are journaled on an axle 12 mounted in the frame,and the pe ripheries of said friction wheels are normally in contact sothat rotary motion is communicated to the wheels l1 from the wheels 9.

On the shaft 12 cams 13 are secured, said cams being rotated with saidshaft 12. The cams 13 extend through a slot 14 in the frame work 11 andcome into contact ateach revolution with a pair of trunnions 15 on thedrill shaft 16. The trunnions 15 are provided with rollers 17 to reducethe friction upon the cams 13. The drill shaft 16 is surrounded by arecoil spring 18, and con nected to the shaft 16 is a drill holder 19provided with a clamp 20 for securing the drill tool in place.

A projecting spring 21 surrounds the shaft 16, one end of said springbearing against a collar a connected to an inclosing tube 23 by a screw6, while the opposite end of said spring bears against a collar 0secured to the shaft 16 by a pin cl. Slots 22 are formed in the tube 23,and the trunnions 17 project through these slots, said trunnions beingformed upon a sleeve 6 mounted loosely on the shaft 16. A rifle bar f isdisposed in a recess in the end of the shaft 16, said rifle bar having ahead 9 adapted to contact with a stop collar h secured to the tube 23.Fitted in the end of the tube 23 is a plug 2', against which the head 9of the rifle bar f bears when the shaft 16 is in its retracted position.A recoil spring 18 surrounds the shaft 23 and bears at its ends againstcollars is, Z secured in the tube 23.

The tube 23 is secured to the frame 11 by means of plates 23 throughwhich bolts 24 extend, the heads of said bolts being connected to theframe 11, and nuts 25 being adjustable upon the ends of said bolts.

In order to move friction wheels 9 and 11 out of contact, we haveprovided a lever 24 pivoted at 25 to a bracket 26 on the end of the tube23, said lever being pivoted at 27 upon a bracket 28 connected to themotor 5. A rack bar 29 provided with rack teeth is also secured to themotor, and a spring pawl 30 connected to the handle 31 of the lever 2ais adapted to engage the teeth of the rack bar. The lever 24 is operatedto move the friction wheels 9 and 11 into and out of contact.

The operation of the machine may be briefly described as follows: WVhenthe friction wheels 9 and fl" are in contact, the cams 13 rotate in thedirection indicated by the arrows in Figs. 5 and 6, said cams coming incontact with the rollers 17 of the trunnions 15 will push said trunnionsbackward against the tension of the spring 21, and when released, as thecams pass the trunnions, the drill tool is driven forward by theexpansion of said spring, and the drill tool strikes the bottom of thehole in the rock. \Vhen the trunnions are being moved backwardlv, thehead y of the rifle bar is brought into contact with the plug i withsufficient stress to create friction between said head and plug and holdthe head against turning during the final backward movement of the drillshaft. During the time the rifle bar is held against rotation, the drillshaft is moved or rotated sufficiently to give the drill tool a turn inthe drill hole.

Our invention is of simple construction, is light in weight, operatesquickly and eflicientlv for its purpose, and can be manu factured atcomparatively slight cost.

Having thus described the invention, what is claimed as new, is

1. In a rock drill, the combination of a frame, a motor provided with apiston rod, a pair of friction gear wheels connected to said rod, ashaft journaled in theframe, friction gear wheels mounted on the shaft,cams on said shaft, a drill shaft provided with oppositely disposedtrunnions, a slotted tube for supporting said shaft, a spring withinsaid tube, and means for moving said motor, piston rod and frictiongear'wheels connected thereto for throwing the drill into and out ofoperation.

2. In a rock drill, the combination of a frame, a guideway on the frame,a motor mounted to slide in the guideway, a piston rod. friction gearsconnected to said piston rod, a shaftjcams on said shaft, friction gearwheels on said shaft, a drill shaft provided with oppositely disposedtrunnions to be actuated by said cams, and a lever for sliding themotor, piston rod and friction wheels into and out of contact with thefriction wheels on the cam shaft.

3. In a rock drill, the combination of a motor, friction gear wheelsactuated by said. motor, a cam shaft, friction gears on the cam shaft,means for shifting the motor and friction gear wheels connected theretointo and out of contact with the friction wheels on the cam shaft, adrill shaft, and trum'iions c011- nected to the drill shaft in the pathof move ment of said cams.

In testimony whereof we aflix our signatures in presence ef twowitnesses.

RALPH F, YOURTEE. KYILLIAM MAULL.

Vitnesses WILLiAM E. GAIJLFIELD, JOHN M. KELLY.

